docs: def handle_command_line(options):
      """
      act upon command options
      """
      options = merge(options, constants.DEFAULT_OPTIONS)
      engine = plugins.ENGINES.get_engine(
          options[constants.LABEL_TEMPLATE_TYPE],
          options[constants.LABEL_TMPL_DIRS],
          options[constants.LABEL_CONFIG_DIR],
      )
      if options[constants.LABEL_TEMPLATE] is None:
          if options[constants.POSITIONAL_LABEL_TEMPLATE] is None:
              raise exceptions.NoTemplate(constants.ERROR_NO_TEMPLATE)
          else:
              engine.render_string_to_file(
                  options[constants.POSITIONAL_LABEL_TEMPLATE],
                  options[constants.LABEL_CONFIG],
                  options[constants.LABEL_OUTPUT],
              )
      else:
          engine.render_to_file(
              options[constants.LABEL_TEMPLATE],
              options[constants.LABEL_CONFIG],
              options[constants.LABEL_OUTPUT],
          )
      engine.report()
      HASH_STORE.save_hashes()
      exit_code = reporter.convert_to_shell_exit_code(
          engine.number_of_templated_files()
      )
      return exit_code